If it is an ordinary LED, then it only draws a small current and low voltage. You can reduce mains AC using the capacitive drop method.
(Caution: Since the wiring is not isolated from high voltage, you must insulate the project from risk of anyone touching it.)
Or several LED's can be strung together. It will use no more current than one LED. A single capacitive drop method will work here. And by arranging two strings in opposite polarity, you can utilize both directions of the mains AC.